int posix_memalign(void **memptr, size_t alignment, size_t size) {
if ((1 << log2_int(alignment)) != alignment) {
return EINVAL;
}
*memptr = allocator_aligned_alloc(allocator_get_global(), alignment, size);
if (!*memptr) {
return ENOMEM;
}
return 0;
}
void *aligned_alloc(size_t alignment, size_t size) {
if ((1 << log2_int(alignment)) != alignment) {
errno = EINVAL;
return NULL;
}
void* ret = allocator_aligned_alloc(allocator_get_global(), alignment, size);
if (!ret) {
errno = ENOMEM;
}
return ret;
}
//length of S[i]
int shuffle_p(int y_num,int tag_length)
{
return 3*log2_int(tag_length)+2*log2_int(y_num);
}
static inline int
main_fft(float *rex, float *imx, int n)
{
int i, ip, j, k, m;
int le, le2;
int nd2;
float si, sr, ti, tr, ui, ur;
nd2 = n / 2;
if (n <= 0 || rex == NULL || imx == NULL)
return -1;
/* Bit rev sorting
* Idea from Smith Scientist and
* Engineers guide to DSP
* second edition
*/
j = nd2;
for (i = 1; i < n - 1; i++) {
if ( i < j) {
tr = rex[j];
ti = imx[j];
rex[j] = rex[i];
imx[j] = imx[i];
rex[i] = tr;
imx[i] = ti;
}
k = nd2;
while (k <= j) {
j -= k;
k >>= 1;
}
j = j + k;
}
m = log2_int(n);
le = 1;
for (k = 1; k <= m; k++) { //Each stage
le2 = le;
le <<= 1;
ur = 1;
ui = 0;
sr = cos(M_PI / le2);
si = -sin(M_PI / le2);
for (j = 1; j <= le2; j++) { //Each SUB DFT
for (i = j - 1; i < n; i += le) { //Each butterfly
ip = i + le2; //Butterfly
tr = rex[ip] * ur - imx[ip] * ui;
ti = rex[ip] * ui + imx[ip] * ur;
rex[ip] = rex[i] - tr;
imx[ip] = imx[i] - ti;
rex[i] = rex[i] + tr;
imx[i] = imx[i] + ti;
}
tr = ur;
ur = tr * sr - ui * si;
ui = tr * si + ui * sr;
}
}
return 0;
}
